Research On The Technology Of Relative Locating For POS In The Wireless Cellular Mobile Network

As the application of wireless POS is being promoted,the customers and supervision department,such as the bank,are paying more and more attention on the security of using the wireless POS in different area.And the demand of limiting the use area of wireless POS and preventing it from moving it out of the area has shown up.It means that the location technology in wireless POS is becoming more zand more important.And doing research on the location technology which can meet both the need and the scene of wireless POS has benefit on both aspects of technology accumulation and economic income for the company.In order to meet the need of limiting the use area of wireless POS and prevent it from being moved out of this area,a relative locating algorithm is realized in this research.This algorithm,whose complexity is O(n),is realized locally on the existing resources of the software and hardware of the wireless POS.And this algorithm is independent of any 3rd party database or server,since it is executed based on the information of base stations in the wireless environment of the wireless POS.Therefore,the final design is guaranteed to be used in low cost independently for a long time,and it can be transplanted to both high-end and low-end products.This research is based on GSM and CDMA systems.In GSM,CGIs of the main base station and adjacent base stations,which are acquired through the module of collecting wireless environment information,are used in the relative locating algorithm for locating.One of the innovation points of this research is proposing a design of replacing CGI by the combination of PN to realize relative locating in CDMA.This design can solve the problem of directly transporting the locating algorithm to CMDA which is caused by the fact that CGI information of adjacent base stations can't be obtained in CDMA.Another innovation point of this research is that the misdiagnosis rate,stability and accuracy of the relative locating algorithm are optimized as follows.The misdiagnosis rate is reduced by the design of automatically updating information of legal area,which is also helpful for the wireless POS to adapt to kinds of wireless environments.The stability of relative locating is improved by realizing many-to-many match algorithm and the design of enlarging the set of legal location information automatically.And the contradiction between stability and accuracy is solved by adding the threshold value to the algorithm,adjusting the threshold value and the upper limit of the set of legal location information according to the attribute of geographical location,so the stability and accuracy get balanced.Finally,this research proves the design of this research can realize the relative locating in both GSM and CDMA.And it has low misdiagnosis rate,high stability and enough accuracy by using the combination of simulation test and actual test.So,it can meet the need,which means it can be used in commercial.